Does 3500 Calories Equal One Pound?

We still hear it all the time – that 3500 calories is equal to one pound of body weight.

The thought might be appealing, that one can simply create a 500 calorie per day deficit by either cutting 500 calories from their diet, adding 500 calories per day of exercise, or a combination of both.

After one week, the deficit of 3500 calories (500 calories x 7 days) should result of 1 pound of weight loss. Bada Bing, weight loss!

Others use the simple calorie calculation to determine how much exercise they need to 'burn off' their previous dietary indulgence.

Truth be told, despite it's simplicity and popular belief, the 3500-calorie-rule has been busted – 3500 calories does not equal one pound of weight loss.

The 3500-Calories-Rule Put to the Test

A study back in 2013 put the 3500-calorie-rule to the test by looking at different weight loss experiments conducted in confinement where the participants were fully monitored at all times, or underwent stringent, objective energy intake measurements.¹

On average, participants were consuming 2876 calories/day, and prescribed to eat 1409 calories/day – creating a deficit of 1439 calories/day. On average, they ate this way for 65 days (31-93 days).

Based on their 3500-kcal-rule, participants should have lost 27.6 pounds. However, they actually lost 20.1 pounds.

Participants lost 7.5 pounds LESS than the 3500-kcal-rule would have predicted. Thus, the 3500-kcal-rule OVERESTIMATED weight loss.

The authors conclude, "the majority of subjects exhibited substantially less weight loss than the amount predicted by the 3500-kcal-rule."¹

Other studies have since supported the inaccuracy of the 3500-calorie-rule.²

Unfortunately, the 3500-calorie-rule as an accurate assessment of energy intake, expenditure, and weight loss is still passed around in fitness and health circles, online, on health-related websites, through textbooks, and even scientific publications.

If you are a fitness, health, medical professional, or dietitian - there are more accurate models to be used. If interested, see here and here.^1,2

It's Complicated, or Is It?

The 3500-calorie-rule fails to be accurate, because weight loss or gain is complicated, both conceptually and mathematically. 

If you are interested, you can venture into the dynamic, mathematical discussions of why the 3500-calorie rule does not work.

Or, you can keep things simple, and eat real food, not too much, mostly plants.³

Bada Bing, weight loss!

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References

1. Thomas, D. M., Martin, C. K., Lettieri, S., Bredlau, C., Kaiser, K., Church, T., ... & Heymsfield, S. B. (2013). Can a weight loss of one pound a week be achieved with a 3500-kcal deficit? Commentary on a commonly accepted rule. International Journal of Obesity, 37(12), 1611-1613.
2. Dhurandhar, E. J., Kaiser, K. A., Dawson, J. A., Alcorn, A. S., Keating, K. D., & Allison, D. B. (2015). Predicting adult weight change in the real world: a systematic review and meta-analysis accounting for compensatory changes in energy intake or expenditure. International Journal of Obesity, 39(8), 1181-1187.
3. Pollan, M. (2007). Unhappymeals. New York Times Magazine (Jan. 28). http://www.nytimes.com/2007/01/28/magazine/28nutritionism.t.html?pagewanted=all